一、简单一键导出Excel

直接给出生成效果

作者本人项目Demo源码

在这里插入图片描述

Empty，这个很关键

因为是通过empty上的 @ExcelProperty注解生成表头的，excel中的数据也需要使用这个类导入

package com.ljj.empty;

import com.alibaba.excel.annotation.ExcelProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @Author lijunyun
 * @Date 2022/10/26 10:20
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class StudentEmpty {

    @ExcelProperty(index = 0,value = "学生id")
    private String id;
    @ExcelProperty(index = 1,value = "姓名")
    private String name;
    @ExcelProperty(index = 2,value = "年龄")
    private Integer age;

}

controller层

用的是 alibaba 的工具类，按照这个import就能导入适当的依赖了，大家在maven自行导入。

package com.ljj.controller;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.write.metadata.WriteSheet;
import com.ljj.empty.StudentEmpty;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.util.LinkedList;
import java.util.List;

/**
 * @Author lijunyun
 * @Date 2022/10/11 17:25
 */
@RequestMapping("/test")
@RestController
public class TestController {


    @GetMapping("")
    public String test01() {
        return "test01,端口9001";
    }

    @GetMapping("/ExportExcel")
    public void ExportExcel(HttpServletResponse response) {

        OutputStream outputStream = null;
        try{
            List<StudentEmpty> data=new LinkedList<StudentEmpty>();
            data.add(new StudentEmpty("1","张三",18));
            data.add(new StudentEmpty("2","小明",19));
            outputStream =response.getOutputStream();
            response.setHeader("Content-disposition","attachment;filename=tableStructureInfo_"+".xlsx");
            ExcelWriter excelWriter= EasyExcel.write(outputStream).build();
            WriteSheet writeSheet=EasyExcel.writerSheet(0,"表结构").head(StudentEmpty.class).build();
            excelWriter.write(data,writeSheet);
            excelWriter.finish();
        }catch (IOException e){
            e.printStackTrace();
        }finally {
            if (outputStream !=null){
                try {
                    outputStream.close();
                }catch (IOException e){
                    e.printStackTrace();
                }
            }
        }

    }

}

EasyExcel类的多种使用方式

快速生成Excel，这里举多种方式

EasyExcel.write(outputStream).head(StudentEmpty.class).sheet(1,"表结构1").doWrite(data);

EasyExcel.write(outputStream,StudentEmpty.class).sheet(2,"表结构2").doWrite(data);

快速生成Excel，一个Excel生成多个表

WriteSheet writeSheet=EasyExcel.writerSheet(1,"表1").head(StudentEmpty.class).build();
WriteSheet writeSheet01=EasyExcel.writerSheet(2,"表2").head(StudentEmpty.class).build();
EasyExcel.write(outputStream).head(StudentEmpty.class).build().write(data,writeSheet).write(data,writeSheet01).finish();

二、导入Excel生成List<>数据

controller层，简单写法

    /**
     * 导入用户信息
     * @param file
     * @throws IOException
     */
    @PostMapping("/excelImport")
    public void excelImport(MultipartFile file) throws IOException {
        //调用方法实现读取
        List<StudentEmpty> lists=EasyExcel.read(file.getInputStream()).head(StudentEmpty.class).sheet().doReadSync();
    }

监听器写法（观察者模式），稍微麻烦

观察者，数据处理在这个类中执行

package com.ljj.other;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.ljj.empty.StudentEmpty;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import com.alibaba.fastjson.JSON;


import java.util.ArrayList;
import java.util.List;

/**
 * @Author lijunyun
 * @Date 2022/10/26 13:09
 */

@Slf4j
@Service
public class ExcelItemListener extends AnalysisEventListener<StudentEmpty> {

    /**
     * 批处理阈值
     */
    private static final int BATCH_COUNT = 5;
    List<StudentEmpty> list = new ArrayList<StudentEmpty>(BATCH_COUNT);

    @Override
    public void invoke(StudentEmpty excelItem, AnalysisContext analysisContext) {
        log.info("解析到一条数据:{}", JSON.toJSONString(excelItem));
        list.add(excelItem);
        if (list.size() >= BATCH_COUNT) {
            importItemInfo(list);
            list.clear();
        }
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        importItemInfo(list);
        log.info("所有数据解析完成！");
    }


    public void importItemInfo(List<StudentEmpty> infoList) {
        //导入操作---新增公司和项目数据
    }
}

controller 层，不做excel的数据处理

    /**
     * 导入用户信息
     * @param file
     * @throws IOException
     */
    @PostMapping("/excelImport")
    public void excelImport(MultipartFile file) throws IOException {
        //调用方法实现读取
		EasyExcel.read(file.getInputStream(),StudentEmpty.class,new ExcelItemListener()).sheet().doRead();
}